Apparatus for grinding and smoothing glass.



W. L. KANN.

APPARATUS FOR GRINDING AND SMOOTHING GLASS.

APPLICATION FILED APR. 24. \914.

1 269,455. V Patented June 11, 1918.

2 SHEETS-SHEET l.

WITNESSES INVENTOR W. L. KANN. APPARATUS FOR GRINDING AND SMOOTHING GLASS. APPLICATI ON FILED APR. 24. 1914.

l ,26 9,455 m Patented June 11, 1918.

2 SHEETSSHEET 2.

WITNESSES Q INVENTOR Maw/M 4 hm WILLIAM L. KANN, OF PITTSBURGH, PENNSYLVANIA.

APPARATUS FOR GRINDING AND SMOOTHING GLASS.

Specification of Letters Patent. Patented June 11, 11918.

Application filed April 24, 1914. Serial No. 834,102.

To all whom z'tymay concern:

Be it known that I, \VILLIAM L. KANN, a citizen of the United States, and resident of Pittsburgh, Allegheny county, State of Pennsylvania, have invented certain new anduseful Improvements in Apparatus for Grinding and Smoothing Glass, of which the following is a specification.

This invention relates to machines for grinding and smoothing plate glass and has particular reference to the means for handling the sand or abrading material and grading the same. Heretofore the practice has been to apply the sand used in such machine in as coarse a condition as was possible to obtain it and then use six to eight finer grades until the application of the final grade leaves the glass almost polished. As a matter of necessity and economy the sand used and crushed and ground down in the process of rough grinding is later used again for the finer grinding. Generally the grinding machine has a ditch arranged about its circumference into which the sand and water which have been used are thrown from the grinding tables by centrifugal force. The heavy sand de-' posits immediately in this circular ditch and is returned to the table as long as there is enough coarse grit in it to do heavy grinding, while the finer grades flow out of the ditch into a main ditch from which they are flowed into a series of collecting pits where they are graded according to their coarseness and the. resultant material is used in all machines for subsequent final grinding. In such a system it is usual to connect the discharge from all machines into one set of grading pits. The fine sand or grading'pits are divided by partitions and as the, sand and water flow into the pits the grades which will be deposited by gravity into each pit is determined by the space between the partitions and the height thereof. The number of machines varies greatly; each machine varies in its process from rough grinding to fine smoothing. Sometimes all of the machines are running and, sometimes only part, so it can be readily seen that the amount of sand and the amount of water used with the sand is a constantly varying quantity, as a consequence of which the grades of sand dein the machine posited in the different settling pits will vary with the fluctuating flow of the water, the result being that when the flow is slowest there is considerable finer sand deposited in the pits for the coarse sand, and when the flow of the water is swift the reverse action takes place; that is, there is considerable of the rough sand carried over into the pits intended for the finer sand. The first action is not very harmful, but it decreases the efiiciency of the coarser grades.- The second action, however, is very harmful as the mixing of the coarse grades with the finer grades scratches the glass and retards the finishing making it necessary to do the operation over again, in part or whole, as only glass which is uniformly properly smoothed will make a desired fine polish on plate or other glass.

In the present application the arrangement for utilizing the coarse sand and the used sand differ from the usual arrange ment and consists broadly in feeding a sufficient amount of new sand to a hopper or other suitable receptacle convenient to the grinding table and cutting off the supply of new sand. The batch of new sand in the hopper is then used in the same and only one machine for both the grinding and smoothing operations, no new sand being mixed with the old, and by such a continuous operation, a predetermined or fixed result is assured each time. By the arrangement of this invention, the sand is, in the process of grinding, ground finer and finer and graded until the glass is smoothed ready for polishing, when the sand is too fine for further use and may be flowed off. The grading of the sand as it is ground and reground in the machine is done separately for each batch of sand and each machine,

and the head of water and other factors" pits showing the grinding, smoothing and polishing machines in elevation; Fig. 3 1s a detail, foreshortened view of the telescopic pulsator or elevating device; Fig. 4: is a detail plan view of the grading hoppers; and Fig. 5 is a sectional view of the same.

In the drawings, 10 and 11 designate two rotatable grinding tables or platforms of the .usual or any preferred construction and of which there may be any number. The tables 10 and 11 support the glass plates and have the rotating pairs of rubbing or grinding disks 12 and 13 arranged to cooperate therewith in the well known manner, as is clearly shown. The rubbing disks 12 and 13 are supported for rotation in frames 14 and 15 arranged to extend over the grinding tables 10 and 11. A ditch or gutter 17 17 is provided beneath each of the tables 10 and 11 and extends beyond the circumference of the tables a short distance to catch thesand as it is thrown from the tables by centrifugal force. Suitable operating mechanism for these parts (not shown) may be provided. New unused sand from a supply or'storage bin 18 is arranged to be discharged through a screen 20 of suitable mesh into a'new sand pit 19 which also holds a supply of water. Water may be supplied to the pit 19 in any suitable manner, as by means of the flexible hose indicated at 19. The pumping mechanism which extends into the pit or receptacle 19 comprises a stationary tubular portion 21 supported at the top of the well and having the discharge branches 22. As shown in Fig. 3, telescopically connected to the tube 21 there is a lower movable pipe 23 which may be raised and lowered into section 21 so as to adjust its position with reference to the bottom of the pit 19. Extending down through the 'section 21 and connected to spiders 230 and 231 rigidly mounted at opposite ends of the .movable,member 23 and extending almost to the lower end of the section 23 there is a compressed air pipe 24 which at its upper end is'flexibly connected to a compressed air supply 25. In operation the compressed air is discharged into the lower portion of the elevator tube and by creating an upward current therein, will cause the sand and water to rise and discharge through the outlet pipe 22. The pipe 23 is raised and low; ered by moving the pipe 24 by means of a counterbalance weight 26 which is connected to the upper end of the compressed air pipe 24. The latter andthe lower section 23 of the telescopic water and sand elevator are maintained at any desired adjustment. The elevating device may be separated from the inlet thereto by a vertical partition 27, which divides the pit 19 into two compartments. The partition is adjustable so that it can be moved into'several positions as shown in dotted lines, whereby the sand may be complished by the upward pressure and as a result, the new sand is fully effective and clean. The lower end of the partition may be adjusted to any height above the bottom of the pit 19. The movable partition is advisable in case it is desired to obtain a partial classification as well as a cleansing of the sand in the pit 19. It may, however, be entirely omitted, and this has been done in practice. Vhen the partition is used, it is possible to control the speed of the rising current and by that means control and classify the sand contained in the stream according to its weight or specific gravity. This is due to the variation of the cross section of the pit compartment in which the elevator device is located. The clean sand delivered from the discharge pipe 22 is conveyed through pipes 28 to a new sand hopper 29 or 29 arranged in any convenient position above the tables 10 and 11, to deliver the sand to the latter. lVhen suflicient new sand has been delivered to grind the glass level the new sand supply is turned off and the sand used in coarse grinding is reused. Any excess of new sand runs over into the receptacle 30 and is returned to the pit 19 by the pipe 31. The sand dis- I charging on to the tables 10 and 11 in its 100 grinding action is thrown outwardly and with the water discharged into the ditch 17 17, from which it is delivered through screens 32, 32 into separate pits 33 and 34,

similar in construction to the pit 19 and which form preliminary collecting chambers. Each of the pits or chambers 33 and 34 and as many more as there are grinding machines is provided with an arrangement for elevating sand therefrom and movable partitions as is provided in the pit 19. These partitions may also be dispensed with, and this has been done in practice. They are only useful, in case it may be desired,

for any reason, to introduce new sand di- 11o reptly into these pits in starting the cycle or-1n case it is desired to obtain a partialgrading or classification of the sand in these plts.

The elevating device 35, located in the pit 33 has its discharge end connected, to the pipe 36, which delivers sand from the pit 33 into a hopper 37, located above the table 10. A hopper 37 above the table 11 receives sand from the pit 34 through the elevating mechanism 38', in the same. manner. The hoppers 29 and 37 are arranged to discharge into a hopper 46, which The hopper 37 is connected by a trough 38 with. a series of classifying or grading hoppers 39, 40, 41, and 42, all of which have a slime overflow connection 43 with the Waste flume 44. The partitions between the grading hoppers are of varying heights from hopper 39 to hopper 42, as shown in Fig; 5. Each of the grading hoppers has a valved connection with a pipe 47 which discharges into a hopper 46, for delivery to the grinding devices. In the successive grinding the plate, only the coarser materials are used over and over again, and as a consequence, become gradually finer and are perfectly graded in the grading hoppers 39' to 42 so that finally only the fine material without any coarser particles will be available for fine grinding. The slimes are therefore continually separated from the coarser particles in each cycle, as the sand is circulated through the apparatus. All excess of water in the wells 33 and 34 is conducted to the waste flume 44 by the overflow connections 45 and 45, thereby maintaining a constant head of water for grading purposes. To maintain the stream of w ater through the elevating devices 35 and- 38 uniform, the air supply used in elevating the water is kept at a constant pressure. Similar grading hoppers 39, 40', 41 and 42 are provided above the table 11. and a slime overflow connection 43 discharges into the waste 44.

The grading boxes are preferably provided with removable partitions 50, over the upper edge ofwhich the overflow from one box or compartment to another takes place. These partitions are made removable, so that apparatus of any desired height can be used interchangeably, thus separately controlling the grading action in each tank or compartment. I also preferably provide the compartments with the false sides 51, which can be seated in any one of a number of different guides 52, so as to vary the cross sectional area of each tank or compartment. This enables further independent control of the grading action in each tank or compartment, it being obvious that when the cross sectional area of any compartment is reduced, the flow from one compartment to the other is changed and only the relatively coarser particles of sand will be separated out in that compartment, the relatively finer portions being carried that much more quickly into the next compartment. By this arrangement,I can obtain a widely different grading action in a single set of grading tanks or compartments.

. I also preferably provide each set of grading tanks or compartmentswith an overflow 53, which communicates with the overflow 43 or 43, and alsoby means of the connection 53, with the pit 33 or 34. The last 35 grading tank or compartment is also prefgrading boxes or tanks.

erably provided with a discharge connection 54, leading to the ditch or gutter 17. By this arrangement of overflows, any unused portions of the various separations in the grading tanks can be directed into the pits 33 or 34, thereby leaving no portion of the original batch of material in storage or in the grading-system to contaminate or affect any succeeding operations. In the starting of the next operation for such unused portions of the abrasive, irrespective of grades or sizes, the operation can be directed to the unused abrasive receptacles 37,v 37, from which the operation is again started of making the respective grades or sizes in the If it is desired to conduct the graded material in any one of the graded boxes or .all of them into the system by the overflow 54, it can be directed into the circular ditch or gutter 17 or 17, and fromthere conducted to the pit 33 or 34, without the necessity of passing the said material through the conductors leading to the table. At any time that it is desired for any'reason to clean the entire system of the abrasive and water, material can thus be conducted from the grading boxes by the overflow 53 into the passage 43, from there into waste flume 44, into the sewer.

\Vhen partitions are used in the pits 33 and 34 and new sand is introduced directly into these pits at the beginning of a cycle, the sand may be carried directly to the grinding table, without first going through the grading tanks, by the provision of a valved connection 55, leading from each of said pits to the corresponding grinding table.

Likewise, I may provide for a complete circulation from the pit 19 to each grinding table by providing connections 56 (shown as branches of the pipe 31) leading to each table; and by providing return passages 57 from the ditches 17. 17 to the pit 19. Suitable valves 58 are provided for the pipes 56 for opening or closing them; and the return passages are provided with gates 59 so that the flow from the ditches 17,17 can be returned either to the pit 19 or to the respective pits 33, 34.

The various connections render the apparatus exceedingly flexible in its adaptation to various conditions and emergencies.

The use of an elevating device of the character herein shown and described having a telescopic lower section enables me at any time while the machine is in service to raise the intake end of this section above the level of the abrasive in the preliminary collecting tank or 34, and by the operation of said device to circulate a flow of clear water throughout the system. In this manner; I can very easily and readily clean out the abrasive circulating system at any time deand air pressure and telescopic elevating device used inthis combination, the grading of the abrasive can be absolutely com I trolled. When no more sand is required out of either pits 19, 33 or 34 in the operation and only water is required to finish the grades in the various hoppers, the telescopic member of the elevating device may be lifted away from the sand contact in the pits while the operation is going on and without intermission.

In the arran ement shown, each grinding and smoothlng machine is a unit complete in itself in which the whole process of rough grinding, fine grinding, smoothing and gradin of the material is carried on. Each machine is independent of the action of its neighbors and by applying a constant head of water, the grading of the abrasive material both in the pump pits and in the fine sand-supplying boxes can be predetermined and regulated. The elevatin device, the fixed head of water and the pressure, in connection with the grading tanks, make it possible to absolutely regulate the rading of the sand, and thereby permit tfie use of the sand from coarse grinding down to smoothing, or until the sand has lost its further usefulness. The apparatus described also makes it possible to use for each grinding operation a completely new fresh batch of sand, uncontaminated by sand and slimes remaining from a previous 0 eration. In each operation the sand is pre erably so manipulated that the batch is used up and carried ofi as slimes. Any slight accumulation of sandwhich may remain in the preliminary collecting chambers or. pits at the end of an operation, re-

mains there permanently since it is below the level at which the pump operates.

Any suitable means may be provided in lieu ofthat herein shown and described for supplying the requisite amount of fresh sand for each complete rinding operation.

While I prefer to use t e complete system herein shown and described, because of the numerous advantages the more important of which I have herein pointed out, I desire it understood that within the scope of my broader claims, the system may be widely modified in details and some of the advantages described may not be obtained in such modified systems. vFor instance, in some cases an increased output of a somewhat lower quality of glass may be desired rather than a somewhat lower output of the finest quality; and in such a case, instead of providing a separate grading system for each machine, a grading system may bemade common to two or more machines; So also,

xed air other precautions with respect to the nonmixing of used and unused sands may not be so strictly observed.

I claim:

1. Apparatus for delivering abrasive material, consisting of a preliminary collecting tank provided with a downwardly extending partition at its upper portion, a supply conduit opening to the upper part of said tank at one side of said partition, an overflow conduit leading from the tank at the other side of said partition, a separate-settling and classifying tank, and means for removing abrasive and water from the classifying tank to the settling tank; substantially as described.

2. Apparatus for delivering abrasive material, comprising a preliminary collecting tank, a separate classifying tank having a plurality of compartments, means for removing abrasive and water from the collecting tank and delivering it to the classifying tank, the classifying tank having means whereb the velocity of flow may be varied in different compartments thereof; substantially as described.

3. Apparatus for delivering abrasive'material consisting of a preliminary collect- 'ing tank, a separate classifying tank'having a series of partitions providing settling compartments of varyin heights, communicating above the partitions, means for removing abrasive and water from the lower portion of the preliminary tank to the upper portion of the classifying tank, and means for removing abrasive and water from each settling compartment and supplyying it to a utilizing apparatus, substantially as described.

4. Apparatus for delivering abrasive material, comprising a reliminary collecting tank having means or effecting a partial grading of the abrasive therein, a separate classifying tank, means for removing abrasive and water from the preliminary tank and delivering it to the classifying tank, means for delivering the classified abrasive to a using apparatus, and means for returning abrasive and water discharged by said apparatus to the preliminary tank; substantially as described. I

5. In apparatus for delivering abrasive material to a single machine to be supplied thereby, a collecting chamber arranged to receive the discharge of abrasive and water from said single machine only, a grading tank system, means for removing abrasive stant head of water in the grading tank system, and means for removing the slime from the circulating cycle of water, the abras ve and water circulating system and the grading tank system of said machines being isolated from other machines, whereby the usedsupplying it to the grading tank system, and

means for maintaining a substantially cohstant head of water in the grading tank system, said apparatus being arranged to maintain a continuous circulation of the abrasive material and water from the table to and through the collecting chamber and thence to the grading tank system and back to the table, substantially as described.

7. In apparatus for delivering abrasive material to a single machine to be supplied therewith, a collecting chamber arranged to receive the discharge of abrasive and water from the said machine only, a grading tank system, means for removing abrasive and Water from thecollecting chamber and supplying it to the grading tank system, means for maintaining a substantially constant head of water in the grading tank system, and means for varying the grading of sand lifted from the collecting chamber, the abrasive and Water circulating system and the grading tank system of such machines being isolated from other machines, whereby the used abrasive from said machine is independently graded, substantially as described.

8. In apparatus for delivering abrasive material, a collecting chamber, an elevated grading tank system, means for removing abrasive and water from the collecting chamber and elevating it to the grading tank system, means for maintaining a substantially constant head of Water in the grading tank system, and means for varying the grading action of the grading tank system, substantially as described.

9. In means for supplying abrasive material to apparatus for grinding and smoothing plate glass, the combination of a grinding apparatus, means for supplying new coarse sand and water to said apparatus until a sufficient quantity of such sand has been supplied to efiect the rough grinding of the glass, a grading tank system having 'means for separating the slimes from the sand andwater, means for circulating the used sand delivered from the table through said grading tank system and tank to the grinding apparatus, and means for maintaining a substantially constant head of water in the grading tank system; substantially as described.

10. In apparatus for delivering abrasive material, a ading tank system having a.

plurality o tanks or compartments arranged in tandem, said tanks or compartments having means for varying their cross sectional areas, substantially as described.

11. In apparatus for delivering abrasive material, a grading tank system having a plurality of tanks or compartments arranged in tandenusa-id tanks or compartments hav ing means for varying their cross sectional areas, and also having means for varying their effective depth, substantially as described.

12. In apparatus for delivering abrasive material, a grading tank system comprising a plurality of adJacent tanks .or compartments arranged in series, said tanks or compartments having removable separating partitions between them and also having adjustable side portions, substantially as described.

13. In apparatus for delivering abrasive material, a grading tank system comprising a series of grading tanks or compartments having means whereby the cross-sectional area of any compartment may be changed and also having means for regulating the rate of flow friom one compartment to another, substantially aS described.

14. In apparatus for delivering abrasive material, a collecting chamber, a grading tank system, means for removing abrasive and water from the collecting chamber and supplying it to the grading tank system, said grading tank system having means independent of its inlet opening for returning the Water and abrasive therein directly to the collecting chamber, substantially as described.

15. In apparatus for delivering abrasive material to machines which use the same, a collecting chamber, means for collecting water and abrasive discharged from the machine and returning it to the collecting chamber, a grading tanksystem, means for removing abrasive and water from the collecting chamber and supplying it to the grading tank system, and means whereby the abrasive and Water maybe discharged from the grading tank system directly to the machines or directly to the collecting chamber or directly to a Waste flume, substantially as described.

16. In apparatus for delivering abrasive material, a collecting chamber, a grading system, and means for removing abrasive and .water from the. collecting chamber and supplying it to a grading tank system, said circulating either Water or water and sand from the collecting chamber through the I apparatus, substantially as described.

17. In apparatus for delivering abrasive material, a. collecting chamber, a grad1ng tank system, and a pump for removing abrasive and water om the collecting chamber and supplying it to the gradin tank system, said pump havin an intake e ement which can be, elevated a; ove the abrasive level in the collecting chamber to thereby circulate Water free of abrasive through the system while leaving the abrasive in the collecting chamber, substantially as described.

18. In apparatus for delivering abrasive material, a collecting chamber, a grading tank system, means for removing abrasive and Water from the collecting chamber and supplying it to the grading tank system, and means whereby all the abrasive in the grading tank system may be discharged therefrom at the completion of the operation, substantially as described.

19. In apparatus for delivering abrasive material to a single mechanism to be supplied therewith, the combination of a collecting chamber for receiving the mixed abrasive and water discharged from said single machine only, means for supplying suflicient new abrasive to complete a single grinding operation, a grading tank system, and means for circulating the abrasive and water collected in the collecting chamber through the grading tank system to the table and back to the collecting chamber; substantially as described,

20. Apparatus for delivering abrasive ma terial, consisting of a collecting tank having a movable partition, a separate classifying tank having a movable partition, and means for removingfabrasive and water from the collecting tank to the classifying tank, substantially as described.

21. In apparatus of the character described, the combination with a machine which uses an abrasive and water, of a preliminary collecting chamber for receiving the abrasive and water discharged from the machine, means for returning the abrasive and water from thencollecting chamber to the machine, a new sand pit, and connections whereby water and. sand from the new sand pit maybe circulated to the machine and back to said pit inde endently of the said collecting chamber, su stantially as described.

22. In apparatus for supplying abrasive material to a plate glass grinding and smoothing table, the combination with a grinding table, of a pit forming a preliminary collecting chamber for collecting the sand delivered from the table, a grading tank system, means for removing abrasive and water from the collecting chamber and supplying it to the grading tank system, means for supplying new sand to the grinding table independently of the grading tank system, and means whereby sand from the various portions of the grading tank sys= tem may be delivered back to the preliminary collecting chamber without passing to the table; substantially as described.

23. The combination with a grinding and smoothing machine, of a used sand receptacle, a plurality of grading receptacles arranged in series to overflow one into another and to receive the overflow from the used sand receptacle, the used sand receptacle and the grading receptacles each having means for separately discharging its contents to said machine independently of the other receptacle, and means for collecting the abrasive andwater discharged from the machine and for repeatedly returning such material to the used sand box, substantially as described.

24. The combination with a grinding and smoothing machine, of a used sand-receptacle, a plurality of grading receptacles arranged in series to overflow into another and to receive the overflow from the used sand receptacle, the used sand receptacle and the grading receptacles each having means for discharging its contents to said machine, and means for collecting the abrasive and water discharged from the machine and for repeatedly returning such material to the used sand box, together with means for supplying a batch of fresh abrasive to the machine independently of the used sand and gradingreceptacles, substantially as described.

. 25. Apparatus for delivering abrasive material to a grinding and smoothing machine,

comprising a receptacle for new sand, means for deliwering sand from said receptacle to the grinding or smoothing machine, a series of sand grading receptacles arranged to overflow one into another, means for delivering sand from each of said receptacles to the said machine, means for collecting the sand and water discharged from the machine and for returning it to the grading tank system, and means whereby material from any part of the grading tank system can be discharged to the collecting means without going to the machine; substantially as described. 1

26. Apparatus for delivering abrasive ma,- terial to a grinding and smoothing machine, comprising a receptacle for new sand, means for delivering sand from said receptacle to the grinding or smoothing machine, a series of sand grading receptacles arranged to overflow one into another, means for delivering sand from each of said receptacles to the said machine, means for collecting the sand and water discharged from the machine and for returning it to the grading tank system, and means whereby material from any part of the ading tank system can be discharged to t e collecting means Without going to the machine, said collecting means being isolated against receiving sand from any other grinding or smoothing machine; substantially as described.

27 In apparatus of the character described, the combination with a machine to be supplied with abrasive, of means for supplying new abrasiveto such machine, said means comprising a receptacle through which the new abrasive is passed on its way to said machine, and said receptacle having means for effecting the removal from the abrasive of foreign matter contained therein, substantially as described.

28. In apparatus of the character described, the combination with a machine to be supplied with abrasive, of means for supplying new abrasive to such machine and for removing from such abrasive any contained slimes and foreign matter before the abrasive reaches the said machine, a preliminary collecting vessel for collecting the abrasive and water discharged from said machine, a grading system for the abrasive, means for removing the abrasive and Water from the preliminary collecting VB-S561 and the grading system, and means for delivering the abrasive from the grading system to said machine, substantially as described.

29. In apparatus of the character described, the combination with a machine to be supplied with abrasive, of means for supplying new abrasive to such machine including a receptacle through which the new abrasive passes on its way to the said machine and having means for removing from the abrasive any foreign material contained therein, a preliminary collecting vessel for collecting the abrasive and water discharged from said machine, a grading system for the In testimony whereof I have hereunto set 5 my hand.

\VILLI AM L. KANN. W'itnesses:

lino. B. BLEMING, H. M. (.omvn'. 

